(1) Field of the Invention
The present invention relates to an image production processing apparatus for producing images of a body from various visual points and a structural data generating apparatus for generating structural data used in processes in the image production processing apparatus.
According to such an apparatus, three dimensional images (3D-images) of works of art, such as sculptures and potteries exhibited in a museum, are displayed on a display unit so that the works of art can be appreciated in various directions without going to the museum. In addition, such an apparatus can be applied to a system by which, in electronic shopping, the exterior of an article of commerce can be seen in various directions on a display screen.
A conventional system as shown in FIG. 1 has been proposed as a system by which images of a body from various visual points are displayed. Such a system is formed of a structural data generating apparatus 50 and an image production processing apparatus 60. The structural data generating apparatus 50 has a range sensor 51, a three-dimensional data generating unit 52, a TV-camera 53, a texture data generating unit 54 and a storage unit 55. The range sensor 51 measures a three-dimensional shape of a body T. The three-dimensional data generating unit 52 generates three-dimensional-shape data based on the measurement result of the range sensor 51. The TV-camera 53 takes a picture of the exterior of the body T. The texture data generating unit 54 generates, based on the picture data from the TV-camera 53, texture data representing colors of various parts of the body T. The storage unit 55 stores, as structural data, the three-dimensional-shape data and the texture data which are respectively generated by the three-dimensional data generating unit 52 and the texture data generating unit 55.
The structural data stored in the storage unit 55 is supplied to the image production processing apparatus 60, via a communication line or using a recording medium such as a CD-ROM.
The image production processing apparatus 60 has a storage unit 61, an output visual point setting unit 62 and a projection processing unit 63. The storage unit 61 stores the structural data supplied to the image production processing apparatus 60. The output visual point setting unit 62 sets a visual point of an output image (an output visual point). The projection processing unit 63 produces an image from the output visual point using a projection process. The image produced by the projection processing unit 63 is displayed on a display unit.
According to such a system, an image of the body T from a visual point can be produced from the three-dimensional-shape data of the body T and the texture data thereof using the so-called computer graphics technology (the projection process).
However, in the system described above, the three-dimensional shape measured from a body, such as a distorted pottery, having a complex shape is not necessarily correct. In addition, the texture obtained by taking a picture of the body by the TV-camera does not correctly correspond to positions on the surface of the measured body represented by the three-dimensional-shape data. Furthermore, in a case where a body is actually seen from various visual points, the color of the surface of the body is varied in accordance with position-relationships between a light source and the body with respect to various visual points. However, the variation of the color based on the position-relationships between the light source and the body with respect to various visual points can not be correctly represented by the projection process using a computer system.
Thus, an image of the body T from a visual point, which image is produced as described above, does not correctly correspond to the body actually seen from the visual point. The reality of an image of the body displayed on the display unit of the above system is not necessarily superior.
To eliminate the above disadvantage, the following system can be proposed.
In the system, pictures of a body from various visual points are previously taken and stored. A picture taken from a visual point which is closest to a visual point set by a user (an output visual point) is selected from among the stored pictures and displayed on a display unit. According to such a system, an image corresponding to a picture which was actually taken is displayed. Thus, the user can see an image having superior reality on the display unit.
However, to obtain an image from a visual point which is requested by a user or close to a visual point requested by the user, pictures of a body from many visual points must be taken and stored. Thus, to store the pictures (image data) of the body, a storage device having a large capacity must be used. In a case where pictures (image data) are supplied to the image production processing apparatus via a communication line, the communication line must have a wide band width to transmit a large amount of image data.